Physics 121 General Physics
Concept Quizzes
Chapter 9. Linear Momentum and Collisions

Which of these systems is NOT an isolated system?

	While slipping on a patch of ice a car collides with another car on the ice. (Ignore friction with the ice.) System: Both cars.
	A single car slips on a patch of ice. (Ignore friction with the ice.) System: The car.
	A ball drops to earth. (Ignore air friction.) System: The ball.
	A billiard ball collides with another billiard ball on a pool table. (Ignore friction with the table during the collision.) System: Both balls.

A car accelerates from rest. In doing so the absolute value of the car's momentum changes by a certain amount and that of the Earth changes by

	A larger amount.
	the same amount.
	a smaller amount.
	the answer depends on the friction force between the car's tires and the Earth.

Two carts have masses m and 2m. They move on an airtrack (ignore friction). You push each cart with the same force for the same length of time. Compared to the momentum of the heavy cart (mass 2m) the momentum of the light cart (mass m) is

	four times.
	twice.
	equal to.
	one-half.

Think fast! You've just driven around a curve in a narow street at 60 km/hr when you notice a car identical to yours coming straight toward you at 60 km/hr. You have two options: hitting the other car head on, or swerving into a massive concrete wall, also head on. In the split second before impact you decide to (assume the same amount of KE is lost by your car in both collisions.)

	hit the other car.
	hit the wall.
	hit either one - it makes no difference which.
	consult your lecture notes.

A golf ball is fired at a bowling ball initially at rest and bounces back elastically. Compared to the bowling ball, the golf ball after the collision has

	greater magnitude momentum but less kinetic energy.
	greater magnitude momentum and more kinetic energy.
	lower magnitude momentum and less kinetic energy.
	lower magnitude momentum but more kinetic energy.

A compact car and a large truck collide head-on and stick together.

1. Which undergoes the larger magnitude momentum change?

	Car.
	Truck.
	Same for both.
	Can't tell without knowing the final velocity of the wreck.

2. Which vehicle undergoes the larger magnitude acceleration during the collision?

	Car.
	Truck.
	Same for both.
	Can't tell without knowing the final velocity of the wreck.